During the processing of raw cotton, following initial cleaning and processing and prior to spinning, the cotton fibres are separated from one another on a machine known as a card. The cleaned raw cotton is lifted from a conveyor by a take-in cylinder and transferred onto a main card cylinder, the surface of which carries a large number of wire points, typically at a density of around 1000 points per square inch. The rotating main cylinder carries the cotton beneath a set of stationary pre-carding flats, typically formed of three blades, each blade extending across the cylinder surface parallel to the cylinder axis. Each blade carries a large number of "wires", that is metal strips blanked out to form a number of teeth. The strips are mounted together on a thin bar and clipped to a support.
Beyond the pre-carding flats, the main cylinder passes the cotton beneath a set of revolving flats which may be mounted on a caterpillar-like track. The cylinder then carries the cotton beneath a further set of stationary flats, before a doffer roller transfers the cotton from the main cylinder to a further conveyor which carries the carded cotton on for further processing.
Wire flats provided on continuously operating cards generally have to be replaced every three months. The replacement operation may only be carried out when the card is shut down, resulting in a loss of production. Further, the quality of cotton produced by a card drops as the teeth of the flats are subject to wear.
It is among the objectives of embodiments of the present invention to provide flat blades which have a longer life than conventional wire flats and to provide an efficient method of producing such flats.